/*
 * Copyright (c) 2008-2020 Haulmont.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.haulmont.cuba.gui.model;

import javax.annotation.Nullable;

/**
 * Utility class working with data loaders.
 */
public class DataLoadersHelper {

    /**
     * Returns the loader of master entity instance.
     *
     * @param nestedContainer nested container to start from
     * @return the loader of master entity instance
     */
    @Nullable
    public static DataLoader getMasterDataLoader(Nested nestedContainer) {
        InstanceContainer masterContainer = nestedContainer.getMaster();
        while (masterContainer instanceof Nested) {
            masterContainer = ((Nested) masterContainer).getMaster();
        }

        return masterContainer instanceof HasLoader
                ? ((HasLoader) masterContainer).getLoader()
                : null;
    }
}
